Will the subprime lending meltdown and credit crunch send us into a financial free fall? We asked the sharpest minds in business to share their reactions to the downturn, and their insights on the road ahead.

The following is the selected writings of various investment leaders on current crisis covered by Fortune

Many institutions that publicly report precise market values for their holdings or CDOs and CMOs are in truth reporting fiction. They are marking to model rather than marking to market. The recent meltdown in much of the debt market, moreover, has transformed this process into marking to myth.

Because many of these institutions are highly leveraged, the difference between “model” and “market” could deliver a huge whack to shareholders’ equity. Indeed, for a few institutions, the difference in valuations is the difference between what purports to be robust health and insolvency. For these institutions, pinning down market values would not be difficult: They should simply sell 5% of all the large positions they hold. That kind of sale would establish a true value, though one still higher, no doubt, than would be realized for 100% of an oversized and illiquid holding.

In one way, I’m sympathetic to the institutional reluctance to face the music. I’d give a lot to mark my weight to “model” rather than to “market.”

Watch for buying opportunities by Bill Miller

Chairman and chief investment officer, Legg MasonCapital Management

These sorts of things are what’s known to the academics as “endogenous to the system”–that is to say, they’re normal. They happen usually every three to five years. So we had a freezing up of the market for corporate credit in the summer of ’02. We had an equity bubble just before that. In ’98 we had Long-Term Capital. In ’94 we had a mortgage collapse like we’re having right now. In 1990 we had an S&L collapse. In ’87 we had a stock market collapse. These things flow through the system, and they’re part of the system. I saw one quant quoted over the weekend saying, “Stuff that’s not supposed to happen once in 10,000 years happened three days in a row in August.” Well, I would think that you would learn in Quant 101 that the market is not what’s known as normally distributed. I’m not sure where he was when all these things happened every three or five years. I think these quant models are structurally flawed and tend to exacerbate this stuff.

But these events represent opportunities. When markets get locked up like this, it’s virtually always the case that you’ll have opportunities if you have liquidity. Instead of worrying how bad it’s going to get, I think people should be thinking about where the opportunities might be.

The NYSE financial index is probably the best barometer of what’s to come. The financials tend to be a very good indicator of where the market’s going. They tend to lead the market because they’re the lubrication for the economy. So I think the financial index will tell you if this thing is over, and so far it’s telling you it’s not over. It’s still falling. But just as financials lead on the downside, they will lead on the upside

The most dangerous words on Wall Street by Wilbur Ross

Chairman and CEO, WL Ross & Co

I recently overheard two men arguing about who was better off. One boasted about his new car, the other about a plasma TV and so on, until one proclaimed, “I am better off because I owe more than you are worth.” The second man conceded defeat. This anecdote summarizes the mortgage bubble. Americans spent more than they earned in 2005 and 2006 and borrowed the difference. The federal government did the same. Everyone secretly feared this was unsound but wanted immediate gratification, so there was applause for talking heads who said global liquidity would make these borrowings safe. Alan Greenspan went so far as to suggest that people take out adjustable-rate mortgages.

Liquidity, however, is not about physical cash; it is mainly a psychological state. Subprime problems have consumed only trivial amounts of global cash but already have burst bubbles by shocking lenders. Clever financial engineering effectively had convinced lenders to ignore risk, and not just in subprime. A major hedge fund participated in a loan to one of our companies, but sent no one to a due diligence meeting. So I called the senior partner to thank him and tell him about the non- attendance. He responded, “I know. For a $10 million commitment, it wasn’t worth going to a meeting.”

When subprime issues first surfaced this spring, many major institutions said they had none, but recent quarterly write-offs show they did. They weren’t lying; they just didn’t know what they had. Their embarrassment has brought risk control back into vogue. It was always silly to lend to weak credits at discounted interest rates, and without documenting income and balance sheets and without appraisals. No amount of model building should have enabled Wall Street to take $100 of such paper and alchemize it into securities sold for $103. Models inherently assume a future similar to the past and therefore they fail when multiple standard deviations occur. Subprime models also did not capture ever more lax credit standards nor that real estate might suffer severe and protracted price declines, again proving that the two most dangerous words in Wall Street vocabulary are “financial engineering.”

Now that we have identified the cause of the disease, how severe and how contagious is it? The present $200 billion of delinquencies will grow to $400 billion or $500 billion next year because $570 billion more low, teaser-rate mortgages will reset to market and consume more than 50% of the borrowers’ income. Therefore most of the loans will be foreclosed or restructured. Probably 1.5 million to two million families will lose their homes. Meanwhile, few lenders will put mortgages on the foreclosed houses, so the prices will plummet. Despite these tragedies, total losses will probably be less than 1% of household wealth and only 2% to 3% of one year’s GDP, so this is not Armageddon. However, even prime jumbo mortgages will be more expensive and more difficult to obtain.

Similar excesses occurred in corporate debt markets. Leveraged buyouts were financed with few or no restrictive covenants and with some borrowers able to “toggle,” or issue more bonds to pay interest in lieu of cash. The debt-to-cash-flow ratio hit record highs, and more than 60% of junk bonds issued are rated B or lower. Only 13% of high-yield issuance proceeds was for capital expenditures for expansion–87% went for sponsor dividends, stock buybacks, LBOs, or refinancings, none of which inherently advance credit worthiness. And this exotic lending paid only 2.5% to 3.0% more interest than Treasury bonds’ 5.5%. Therefore investors received only 8% or 8.5% interest on bonds that had a 25% probability of defaulting, the same ignoring of risk as in subprime.

The cause was also the same. Wall Street made $100 of these credits into tranches of securities that sold for $102 or more. Again we had securitization pseudo-alchemy creating fool’s gold. The weakest 5% or so of a $2 trillion universe of leveraged loans and high-yield bonds will crater. This is only 1% of GDP, but lending standards will tighten for a while, just as they did after the telecom bubble burst.

Because of this outlook, WL Ross portfolio companies raised $2 billion this year to eliminate outside financing needs. More recently, we provided a modest $50 million debtor-in-possession financing to American Home Mortgage, the tenth-largest subprime lender, as it entered bankruptcy. Ultimately, we will make a major move into mortgages, because lending to weak borrowers makes sense at premium rates with proper due diligence and appraisals. After Japan’s real estate bubble burst, we used a similar strategy to rehabilitate Kansai Sawayake Bank. It was earning 17% a year on equity after one year, almost twice the return typical of a Japanese bank

Market corrections are coming by Jim Rogers

Founder of the Rogers Raw MaterialsIndex

We’ve had the worst bubble in credit we’ve ever had in American history. As the bubble got bigger and bigger, it spread to emerging markets and leveraged buyouts and all sorts of things. And it hasn’t been cleaned out yet. I don’t think you can have a bubble like this and clean it out in six months or even a year. It has always taken longer.

Look at homebuilders, for instance. Historically, when an industry goes through a retrenchment like this, you have two or three big companies going bankrupt and most of the companies in the industry losing money for a year or two or three. Well, we haven’t gotten anywhere near that in the homebuilding business, so I think that bottom is a long way off. As far as the credit bubble, we have another several months, if not more, of mortgages that are going to reset and people who are going to find themselves with even higher monthly payments. There are many, many more losses to come, most of which we won’t know about for weeks or months.

Normally you have markets go down 10% or so every couple of years. We haven’t had a 10% correction in the stock market in nearly five years. I don’t know if this is the beginning of it, but we’ve got a lot of corrections coming. It wouldn’t surprise me to see a little bounce–say if a central bank cuts rates. But that will just lead to the markets falling further late this year or next year. It would be better for the market, it would be better for investors, and it would be better for the world if we went ahead and cleaned out the system. If they do cut rates in the U.S., it would be pure madness. Because the market’s down 7% or 8% from an all-time high? My gosh, what’s that going to say about the dollar? What’s that going to say to foreign creditors? What’s that going to say about inflation? The Federal Reserve was not founded to bail out Bear Stearns or a few hedge funds. It was founded to keep a stable currency and maintain its value.

I have been and continue to be short the investment banks and the commercial banks. If they bounce up, I’ll probably short more. I’m certainly not buying anything. The market’s only down 8%. I don’t consider that a buying opportunity. The things that I’m short, some people probably think are buying opportunities, but I don’t. I’ve been short the banks for close to a year, and for a while it was not fun. But I added to my positions, and now it’s a lot of fun.